The ability of users to access programs and share data over local area networks (referred to as “LANs”) has become a necessity for most working environments. To improve efficiency and ease of use, certain enhancements may be added to a LAN such as remote wireless access. By providing wireless access, a wireless LAN (WLAN) is formed.
As described in U.S. Pat. No. 5,987,062 issued to Netwave Technologies, Inc., now owned by Nortel Networks Limited, one type of WLAN employs dedicated stations, which are referred to as access points (APs). Therein, each AP is a relay station that includes a radio frequency (RF) transceiver that receives (and transmits) radio data packets over a communication channel from (and to) mobile units within a predetermined, non-adjustable coverage distance. The level of effective isotropic radiated power used by the RF transceiver determines the coverage distance. An example of this AP is a BAYSTACK™ 650 Wireless Access Point produced by Nortel Networks Limited.
Hence, depending on the coverage distance, an AP can share its communication channel with tens or even hundreds of mobile units. This reduces the aggregate amount of data throughput to the mobile units. To improve data throughput, one proposed solution is to implement additional APs within the WLAN. However, this proposed solution may not be applicable, depending on the operating environment.
For example, in order to effectively reuse communication channel frequencies within a WLAN, each additional AP must be placed outside a pollution range associated with its neighboring AP. This “pollution range” is the coverage area determined by both the coverage distance of the AP as well as the coverage distance of any of its mobile units because they communicate on the same communication channel. For a worst case scenario, where the level of effective isotropic radiated power used by the mobile unit is equivalent to the level of effective isotropic radiated power used by the AP, the pollution range is twice the coverage distance, and thus, a maximum of four times the coverage area of the AP. Hence, the additional placement of APs may not be a legitimate solution to data rate throughput problems for a WLAN when there is a high concentration of mobile units within a small area.